The primary objective of this research program is to understand central integrative mechanisms in cortical regions of the mammalian brain. The structures of the olfactory pathway - olfactory bulb and prepyriform cortex - offer advantageous eodels for this objective. Electrophysiological experiments employing microelectrode recordings will be aimed at obtaining further evidence for dendrodendritic synaptic interactions in the olfactory bulb; particular interest will focus on these interactions in short-axon cells of the bulb, as a model for short-axon cells in other parts of the brain. Based on our knowledge of synaptic organization, analysis of unitary responses will be carried out during odor stimulation, with the aim of establishing the neuronal basis of olfactory discrimination. This study will employ an olfactometry apparatus providing for brief stimuli that are spatially restricted, in analogy with stimuli used in other sensory systems. We will attempt to analyze the sequence of synaptic integration of olfactory signals through the olfactory bulb into the central olfactory (prepyriform) cortex. A complementary research program is concerned with photomicroscopical studies of isolated muscle spindles of the frog during stretch, in an effort to shed further light on new models for mechanoelectric transduction.